| Zirconium and its alloys are widely used in aerospace,military and other fields,due to its amazing corrosion resistance,high melting point,high hardness,high strength and other characteristics.With the more widespread use of zirconium,more attention has been paid to the safety of zirconium powder.Therefore,it is important to do the research of the combustion and explosion characteristics of zirconium powder.In this paper,the combustion and explosion characteristics of zirconium powder were studied in different states,which can provide a parameter basis for its essential safety protection.The specific research contents and conclusions are as follows:The minimum ignition temperature of zirconium dust layer was studied by using the hotplate layer ignition apparatus.Results show that the MITL of zirconium is about 310?.The minimum ignition temperature of dust cloud was studied by using Godbert-Greenwald furnace.The MITC of zirconium is about 210?.And the MITC of zirconium hydride is about325?.The minimum ignition energy of dust cloud was studied by using Hartmann tube.The results are as follows.The MIE of zirconium is between 1mJ and 3mJ,and the MIE of zirconium hydride is less than 1mJ.The concentration of zirconium increases gradually in the range of50g/m3 to 500g/m3,with the MIE decreasing first and then increasing.When the concentration is 500g/m3,the MIE is least.Besides,Hartmann tube was used to do the research of the flame propagation.The duration of flame propagation increases with the increase of powder spraying pressure.The maximum flame speed increases with the increase of turbulence intensity.Instead the average flame speed drops off due to the enhancement of turbulence.The combustion and explosion characteristics of zirconium dust cloud in the self-designed20L cylindrical explosive tank was studied.The conclusion are as follows.When the ignition energy increases from 1kJ to 10kJ,the maximum explosion pressure increases from 40kPa to142.5kPa.The maximum explosion pressure keeps increasing with the growth of initial energy.When the concentration of zirconium goes up,the maximum explosion pressure first goes up and then goes down.And the maximum explosion pressure rise rate shows the same trend.When the concentration is 240g/m3,the pressure reaches the peak value of 435kPa.And the maximum rate is 19.9 MPa/s at the concentration of 275 g/m3.Both N2 and Ar have some anti-detonation effect,and the anti-detonation effect of Ar is better than that of N2.The rank of three different materials of explosion suppresion is NH4H2PO4.>ABC>MCA.With the increase of the proportion of H2,the pressure rises gradually first in the mixed system,until the proportion of H2 grows up to 45%.And the pressure gets a peak value 731.6kPa at the time.Then pressure gradually drops off.The combustion and explosion of projectile zirconium powder in open space was studied by using self-made cartridge case.The results are as follows.The deflagration happens but detonation not.The energy generated by 1D and 8gRDX which is 52.82KJ,is over the critical deflagration energy.When the output energy is 193.46kJ?1D+32gRDX?,the flame propagation speed reaches the maximum value 266.7m/s.Flame temperature is up to 352?;Both the flame propagation speed and temperature decrease with the decrease of detonation energy. |
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